I have two quick questions regarding mercenaries. I searched through this forum and found several useful threads - such as this Ultimate Merc Guide V3.0 that answered some of my other questions, but am not too sure about the following three questions:

1) How do I find out what aura level my Act 2 Mercenary has when he has Might, Blessed Aim, Holy Freeze, etc.?

2) I found a mercenary guide that states, "Mercs hired in normal difficulty have better final stats than those hired in Nightmare or Hell, and NM Mercs are better than those hired in Hell." Is this true?

3) A lot of threads have members stating that it is best to hire a mercenary at his or her lowest possible level and level him or her up yourself. I thought this was changed some years ago, and that it doesn't matter at which level a mercenary is hired at. Am I correct?

the guide you linked to answers your questions 1 and 2. Post 5 here for example has all the information for Act 2 Nightmare Might Mercs. In the left most column you find the Merc level, in the right most column you find the corresponding Aura level. A level 55 Merc has a level 10 Might Aura for example.
The stats for all levels are also in the table. Our level 55 Might Merc has 134 strength.
A Blessed Aim Merc, the Offensive Merc in Normal has 138 strength at the same level. You can find his stats in the table in post 4. So yes, Mercs hired in Normal have higher stats than Mercs hired in Nightmare than Mercs hired in Hell.

Regarding your third question: This is also the reason you should hire him in the lowest possible difficulty level. His stats will be higher. This does not mean you should hire the Merc with the lowest possible character level. If you want Holy Freeze or Might this doesn't matter, as Nightmare is the only difficulty level you can hire them in. But a Defiance Merc you can get in Normal and Hell. Here you should always take the Normal Merc for the reasons stated above.

BTW, what has been changed with the 1.11 patch with respect to mercs is that their level restriction upon hiring has been lifted, so you also had to level them before that. That led to the wrong conclusion that they were better because of the leveling process.

the guide you linked to answers your questions 1 and 2. Post 5 here for example has all the information for Act 2 Nightmare Might Mercs. In the left most column you find the Merc level, in the right most column you find the corresponding Aura level. A level 55 Merc has a level 10 Might Aura for example.

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Thank you so much for pointing that out. I looked at those charts for a couple of minutes, but I must have gotten too used to modern spreadsheets, because when the numbers weren't directly below the "Might Lvl" column, I just thought the author didn't include the aura levels!

Regarding your third question: This is also the reason you should hire him in the lowest possible difficulty level. His stats will be higher. This does not mean you should hire the Merc with the lowest possible character level. If you want Holy Freeze or Might this doesn't matter, as Nightmare is the only difficulty level you can hire them in. But a Defiance Merc you can get in Normal and Hell. Here you should always take the Normal Merc for the reasons stated above.

BTW, what has been changed with the 1.11 patch with respect to mercs is that their level restriction upon hiring has been lifted, so you also had to level them before that. That led to the wrong conclusion that they were better because of the leveling process.

Click to expand...

Ah, okay, thanks. I remember there were times years and years ago that I had level 90 characters desperately trying to get my very low level hirelings to level up! I'm glad they've changed that.

I am just coming back to diablo since 1.10. What I remember then was that Hell mercs had static aura strengths, and only normal and NM mercs had auras that increased in level. This meant that a rushed lvl1 character could hire a Hell A2 merc with, iirc, a lvl16 prayer aura. I would usually take advantage of that for my first 20 or so levels, to save on the hassle of using health pots. I do not know if this is still the case in 1.13

I'm new to this forum and relatively new to Diablo 2, only on my first character in Act 2. I had a mercenary that I gave pretty good gear but wanted to try a new one and now want my old one back. How do I get her back? Can I? Is the the gear gone?

In game files and memory, newly hired mercenary's stats and gear replace the old one's, so you cant "get it back". This always makes me paranoid to triple check if I have removed all the merc's gear before hiring a new one.